Hello Alexander,
Thank you for your comments, they are really helpful :)
The command would be: ipa-ldap-updater --schema-file ./01authkey.ldif ?
About the format what would be wrong or what would be the correct format for our file. We were following an freeipa user guide, but perhaps there was something I didn't apply correctly based on the notes: https://www.freeipa.org/images/5/5b/FreeIPA33-extending-freeipa.pdf
Kiitos Kind regards, gcol